Plasticized polyvinyl halides



Patented Aug. 7, 1951 PLASTICIZED POLYVINYL muons Joachim vDazzi, Dayton, Ohio, assignor to Monsanto Chemical Company, St. Louis, M0,, a corporation of Delaware No Drawing. Application August 21, 1950,

Serial No. 180,690

This invention relates to compositions comprising polymers of vinyl halides and relates more particularly to compositions comprising vinyl chloride polymers plasticized with esters of (1',2'- dicarboxyethyl) octadecenoic acid.

A wide variety of plasticizers has been employed for the purpose of improving the physical properties of vinyl chloride polymers. Particular attention has been given to the improvement of flexibility and heat and light stability of such plasticized compositions. In many instances the improvement in flexibility has been obtainable only by sacrificing other desirable properties of an ideal polyvinyl chloride composition, such as low volatility, color and heat stability, water absorption, etc.

Now I have found that very good flexibility, without sacrifice of temperature stability and low volatility, is imparted to vinyl chloride polymers when there are employed with the polymers certain cycloalkyl esters of (1,2-dicarboxyethyl)- octadecenoic acid. Esters of this acid are broadly disclosed in the Clocker Patent U. S. No. 2,188,- 888, and in the article by Ross, Gebhart and Gerecht, appearing in the Journal of the American Chemical Society, p. 1373 (1946). Briefly, they are obtainable by the addition reaction of maleic anhydride with oleic acid or its esters and subsequent esterification. While isomeric products are possible, and the position at which the anhydride residue is attached to the oleic compound is not known, the reaction of oleic acid or of an alkyl oleate with maleic anhydride proceeds probably according to the scheme:

wherein a: is a whole number between 5 and 8 and R is a member of the group consisting of hydrogen, alkyl radicals of from 1 to 8 carbon atoms, the cyclohexyl radical, and the methylcyclohexyl radical.

Esterification of the resulting adduct with cyclohexanol or methylcyclohexanol yields the trialkyl ester which probably has the structure:

Hr-OOOB' 7 Claims. (Cl. 260-318) in which R is selected from the class consisting of cyclohexyl and methylcyclohexyl radicals and Z is selected from the class consisting of R and alkyl radicals of from 1 to 6 carbonatoms, and a: is a whole number between 5 and 8.

Because of uncertainty concerning the position at which the maleic residue is attached to the oleic group, the present esters will be hereinafter referred to without stipulating the position of the (1,2-dicarboxyethyl) group.

As examples of compounds having the above general formula may be mentioned tricyclohexyl (1',2 dicarboxyethyl)octadecenoate, the alky1[1',2 bis(carbocyclohexyloxy) ethyllo c t adecenoates in which the alkyl group has from 1 to 6 carbon atoms, i. e., the methyl, the isopropyl, then amyl or the 2 ethylbutyl [1',2-bis(carbocyclohexyloxy) ethyl] octadecenoate; tris (methylcyclohexyl) (l',2' dicarboxyethyl)octadecenoate, and the alkyl {1',2-bis-[carbo(methylcyclohexyl)oxy]ethyl}octadecenoates in which the alkyl radical has from 1 to 6 carbon atoms, .e. g., the ethyl, the propyl, the butyl or the hexyl {1',2'- bis [carbo (methylcyclohexyl) oxy ethyl} octadecenoate.

The present cycloalkyl (1,2'-dicarboxyethyl) octadecenoates are valuable plasticizers for polyvinyl chloride and copolymers of at least 70 per cent by weight of vinyl chloride and up to 30 per cent by weight of an unsaturated monomer copolymerized therewith, for example vinyl acetate, vinylidene chloride, etc.

Adducts of acyclic olefinic acids and longchained unsaturated acids have been hitherto generaly suggested for use as softening agents. I have now found, however, that esters of the class consisting of tricyclohexyl (1',2'-dicarboxyethyl) o c t a d e c e n oate, tris(methylcyclohexyl) (1,2'-dicarboxyethyl)octadecenoate, also, alkyl [1,2' bis(carbocyclohexy1oxy) ethylloctadecenoates in which the alkyl radical has from 1 to 6 carbon atoms, and alkyl {1,2-bis[carbo(methylcyclohexyl)oxy]ethyl}.octadecenoates in which the alkyl radical has from 1 to 6 carbon atoms are of outstanding value as plasticizers, these esters serving not only to soften vinyl chloride polymers, but also to impart simultaneously a high degree of low temperature flexibility, very good temperature stability and great mechanical strength to these polymers. While many of the esters encompassed by the Clocker patent referred to above are incompatible with polymers and copolymers of vinyl chloride and do not give continuous, homogeneous compositions, the present esters are compatible with vinyl chloride polymore and show no exudation of plasticizer even at plasticizer content of up to 50 per cent. Although the quantity of plasticizer will depend upon the particular polymer to be plasticized and upon its molecular weight, it is generally found that compositions having from per cent to 50 per cent by weight of plasticizer will, in most cases, be satisfactory for general utility. The good flexibility of the plasticized compositions increases with increasing plasticizer concentration.

In evaluating plasticiaer efllciency use is made of the following empirical testing procedures:

Compatibility.-Visual inspection of the plasticize'd composition is employed, incompatibility of the plasticiaer with the polymer being demonstrated by cloudiness and exudation of the plasticizer.

Hardness.A standard instrument made by the shore Instrument Company is used for this determination and expresses the hardness in units from 1 to 100. The hardness of a composition is Judged by its resistance to the penetration of a standard needle applied to the composition under a standard load for a standard length of time.

Low temperature flexibility.-Low temperature flexibility is one of the most important properties of elas'comeric vinyl compositions. While many plasticizers will produce flexible compositions at room temperature the flexibility of these compositions at low temperatures may vary considerably, i. e., plasticized polyvinyl chloride compositions that are flexible at room temperature often become very brittle and useless at low ternperatures. Low temperature flexibility tests herein employed are according to the Clash-Berg method. This method determines the torsional flexibility of a plastic at various temperatures. The temperature at which the vinyl composition exhibits an arbitrarily established minimum flexibility is defined as the Low Temperature Flexibility of the composition. This value may also be defined as the lower temperature limit of the plasticized compositions usefulness as an elastomer.

Volatility.Just as a decrease in low temperature often results in decerased flexibility of a plasticized polymer composition so does a decrease in plasticizer concentration when caused by volatilization of the plasticizer. Hence, plasticizers which are readily volatilized from the plasticized composition as a result of aging or heating are inefficient because upon volaiilization the plasticized compositions become still and hard. The test for plasticizer volatility herein employed is that described by the American Society for Testing Materials under the designation D-744-44T.

The invention is further illustrated, but not limited. by the following example:

Example Sixty parts of polyvinyl chloride and 40 parts by weight of the tricyclohexyl ester of (l,2'-dicarboxyethyDoctadecenoic acid are mixed on a rolling mill to a homogeneous blend. During the milling there was observed substantially no fuming and discoloration. The molded sheet of the mixture was clear and transparent and substantially colorless. Testing of the molded sheet for low temperature flexibility, according to the testing procedure described above, gave a. value of minus 5 C. which value denotes good low temperature properties. Tests on the volatility char. acteristics of the plasticized composition gave a value of 1.25 per cent which showed very good perature characteristics of the composition. The plasticized material had a hardnus of 92 before the volatility test and a hardness of 88 after the volatility test. When subjected to heat at a temperature of 325 F. for a period of 30 minutes the clarity and color of the molded product was substantially unchanged.

Instead of the ester employed in the example above, other esters of (l',2-dicarboxyethyl)- octadecenoic acid with cyclohexanol or methylcyclohexanol gave similarly valuable plasticized polyvinyl chloride compositions. Thus by employing 40 parts by weight of tris (methylcyclohexyl) (1',2' -dicarboxyethyl)octadecenoate or alkyl dicycloalkyl esters such as isobutyl [l',2'- bis(carbocyclohexyloxy)ethyl] octadecenoate or ethyl {l'.2 bis[carbo(methylcyclohexyl)oxylethyl} oetadecenoate with 60 parts by weight of polyvinyl chloride, or with 60 parts by weight of vinyl chloridevinyl acetate copolymer known to the trade as Vinylite there are obtained clear, colorless compositions of very good flexibility and stability.

While the above example shows only compositions in which the ratio of plasticizer to polymer content is 40:60, this ratio being employed in order to get comparable emciencies, the content of ester to polyvinyl chloride may be widely varied, depending upon the properties desired in the final product. For many purposes a plasticizer content of, say, from only 10 per cent to 20 per cent is preferred. The present esters are compatible with polyvinyl chloride over wide ranges of concentrations, up to 50 per cent of esters based on the total weight of the plasticized composition yielding desirable products.

Although the invention has been described particularly with reference to the use of the present cycloalkyl esters of (1',2'-dicarboxyethyl)octadecenoic acid as plasticizers for polyvinyl chloride, these esters are advantageously employed also as plasticizers for copolymers of vinyl chloride, for example, the copolymers of vinyl chloride with vinyl acetate, vinylidene chloride, etc. Preferably, such copolymers have a high vinyl chloride content, i. e., a vimrl chloride content of at least 70 per cent by weight of vinyl chloride and up to 30 per cent by weight of the copolymerizable monomer.

The plasticized polyvinyl halide compositions of the present invention have good thermal stability; however, for many purposes it may be advantageous to use known stabilizers in the plasticized compositions. Inasmuch as the present esters are substantially unreactive with the commercially available heat and light stabilizers which are commonly employed with polyvinyl chloride or copolymers thereof, the presence of such materials in the plasticized materials does not impair the valuable properties of the present esters. The present esters are of general utility in softening vinyl polymers. They may be used as the only plasticizing component in a compounded vinyl chloride polymer or they may be used in conjunction with other plasticizers.

What I claim is:

l. A resinous composition comprising a vinyl chloride polymer plasticized with an ester selected from the class consisting of tricyclohexyl (l',2-dicarboxyethyl)octadecenoate, tris (methlycyclohexyl) (l',2' dicarboxyethyDoctadecenoate, alkyl [1'2 -bis (carbocyclohexyloxy) ethyl] octadecenoates in which the alkyl radical has from 1 to 6 carbon atoms and alkyl{1',2-bls- [carbo (methylcyclohexyl) oxy] ethyl}octadecenoates in which the alkyl radical has from 1 to 6 carbon atoms.

2. A resinous composition comprising polyvinyl chloride plasticized with an ester selected from the class consisting of tricyclohexyl (1',2-dicarboxyethyl) octadecenoate, tris (methylcyclohexyl) 1 ',2'-dicarboxyethyl) octadecenoate, alkyl [1,2' bis(carbocyclohexyloxy ethyl] octadecenoates in which the alkyl radical has from 1 to 6 carbon atoms and alkyl{1',2'-bis[carbo(methylcyclohexyl)oxylethyl}octadecenoates in which the alkyl radical has from 1 to 6 carbon atoms.

3. A resinous composition comprising polyvinyl chloride plasticized with an ester selected from the class consisting of tricyclohexyl (1',2'-dicarboxyethyl) octadecenoate, tris (methylcyclohexyl) (1,2'-dicarboxyethy1)octadecenoate, alkyl [1',2- bis(carbocyclohexyloxy) ethyl] octadecenoates in which the alkyl radical has from 1 to 6 carbon atoms and alky1{1,2' bis[carbo(methylcyclohexyl)xylethyl}octadecenoates in which the alkyl radical has from 1 to 6 carbon atoms, said ester being from to 50 per cent of the weight of the composition.

4. A resinous composition comprising a copolymer of at least 70 per cent by weight of vinyl chloride and up to 30 per cent by weight of an unsaturated monomer copolymerizable therewith, said copolymer being plasticized with an ester selected from the class consisting of tricyclohexyl (1,2-dicarboxyethyl) octadecenoate, tris (methylcyclohexyl) (1,2'-carboxyethyl) octadecenoate,

6 alkyl [1.2 bis(carbocyclohexyloxy)ethylloctadecenoates in which the alkyl radical has from 1 to 6 carbon atoms and alkyl{1,2'-bis[carbo- (methylcyclohexyl) oxy] ethyl}octadecenoates in which the alkyl radical has from 1 to 6 carbon atoms.

5. A resinous composition comprising a copolymer of at least 70 per cent by weight of vinyl chloride and up to 30 per cent by weight of an unsaturated monomer copolymerizable therewith, said copolymer being plasticized with an ester selected from the class consisting of tricyclohexyl (1',2 -dicarboxyethyl) octadecenoate, tris (methylcyclohexyl) (1 ,2 -dicarboxyethyl) octadecenoate, alkyl [1,2' bis(carbocyclohexyloxy)ethy1l octadecenoates in which the alkyl radical has from 1 to 6 carbon atoms and alkyl 1 ,2 -bis [carbo (methylcyclohexyl) oxy] ethyl} octadecenoates in which the alkyl radical has from 1 to 6 carbon atoms, and said ester being from 5 to per cent of the weight of the composition.

6. A resinous composition comprising polyvinyl chloride plasticized with tricyclohexyl (1',2'-dicarboxyethyl) octadecenoate.

7. A resinous composition comprising polyvinyl chloride plasticized with tricyclohexyl (l',2-dicarboxyethyl)octadecenoate, said ester being from 5 to 50 per cent of the weight of the composition.

JOACH'HVI DAZZI.

No references cited. 

1. A RESINOUS COMPOSITION COMPRISING A VINUL CHLORIDFE POLYMER PLASTICIZED WITH AN ESTER SELECTED FROM THE CLASS CONSISTING OF TRICYCLOHEXYL (1'',2''-DICARBOXYETHYL)OCTADECENOATE, TRIS (METHLYCYCLOHEXYL) (1'',2''- DICARBOXYETHYL)OCTADECENOATE, ALKYL (1'',2''-BIS(CARBOCYCOLHEXYLOXY)ETHYL) OCTADECENOATES IN WHICH THE ALKYL RADICAL HAS FROM 1 TO 6 CARBON ATOMS AND ALKYL(1'',2''-BIS(CARBO (METHYLCYCLOHEXY) OXY) ETHYL)OCTADECENOATES IN WHICH THE ALKYL RADICAL HAS FROM 1 TO 6 CARBON ATOMS. 